ABSTRACT We propose to compare phosphatidylethanol (PEth) and Ethyl glucuronide (EtG), and self-reported alcohol use in all participants in the MWCCS and new enrollees and examine their association with 1) HIV outcomes including antiretroviral therapy (ART) adherence and 2) clinical outcomes including liver disease as measured by vibration- controlled transient elastography (VCTE), cardiac arrhythmias and dysfunction, and neurocognitive impairment. Specific aims: ? To compare sex and race/ethnicity differences in PEth, EtG, and self-reported alcohol use ? To examine the association of PEth, EtG, and self-reported alcohol use with liver steatosis and liver fibrosis measured by VCTE. ? To examine the association of PEth, EtG, and self-reported alcohol use with Echocardiograpy measured cardiac dysfunction. ? To examine the association of PEth, EtG, and self-reported alcohol use with neurocognitive impairment. We also propose to expand the MWCCS interview to include more detailed information regarding alcohol use to compare with the objective measures PEth and EtG. We will perform objective measures of alcohol use, including: ? EtG: Use urine samples routinely collected during core visits and stored in the national repository. Testing will be performed at Brad?s lab at NYU. ? Peth: Collect 1 mL of whole blood in a grey top for dried blood spots to be prepared in your specimen processing lab. UCSF will budget for all testing costs and provide supplies to the sites. We will perform single copy HIV RNA testing: ~ 75% of the participants have an undetectable VL based upon a cut-off of 20. By going down to a single copy, we will have a continuous value of HIV VL. It will also allow us to see whether ART adherence might attenuate the association of alcohol with lack of viral suppression. Testing will be performed on reposited samples at the Pittsburgh site.